• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.9 no.4
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• pp.78-85
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• 1995

This paper covers stability and stabilization of Multi-Excited Induction Motor used in numberous electric equipment system of industrial field. The induction motor with multi-excitation has tow sets of three-phase system : One is connected to the AC source to supply most power required at the load, and the other is to the inverter for variable frequency and/or magnitude of voltage. The conventional induction motor is operated under single excitation mode only, that is called induction mode. But in multi-excited induction motor both the induction mode and the synchronous mode are possible, and the proposed multi-excited induction motor can be driven as a synchronous motor by the extra three-phase input. At the synchronous mode the efficiency is improved so higher than that at induction mode or conventional induction motor. The rating of the inverter used for speed control of numberous electric equipment system can be reduced upto one-tenth of that for conventional induction motor. Also the cost and maintenance fee of multi-excited induction motor can be reduced compared to any other motor.

• Journal of KSNVE
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• v.11 no.1
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• pp.76-81
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• 2001

This paper addresses experimental results carried out to investigate the transmission of seat vibration to the head for Korean. Vertical seat vibration in the frequency range of 0.5-30 Hz was applied to a seated Korean male subject. To examine the intra-variable effects on transmissibility, five different postures and three different vibration excitation levels were considered. The applied acceleration and head accelerations of the seated subject were measured simultaneously by using a 6-axes bite-bar. Detailed experimental results of measured transmissibilities are illustrated for each posture and/or vibration excitation level, and they were compared to an International Standard. They are found to allow the identification of dynamic characteristics of Korean seated body for various reat vibration environments. Furthermore, they are expected to be very useful in designing new seats for automotive and railway vehicles and in improving their vibration ride quality.

• Aerospace Engineering and Technology
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• v.8 no.1
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• pp.154-161
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• 2009

Generation of pure and controllable excitation waves to excite the natural fast-growing instability waves has always been a difficult task. For this purpose, a device that is capable of supplying co- and counter-swirl was designed, fabricated, and applied. To incorporate a novel, robust mechanical excitation device that is capable of producing disturbances, mechanically and passively, a novel device was designed and built.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2001.09a
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• pp.373-380
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• 2001

In this research, a controller design method based on optimization is proposed that can satisfy constraints on maximum responses of building structures subject to ground excitation modeled by partially stationary stochastic process. The class of controllers to be optimized is restricted to LQR. Weighting matrix on controlled outputs is used as design variable. Objective function constraint functions and their gradients are computed parameterizing control gain with Riccati matrix. Full state feedback controllers designed by Proposed optimization method satisfy various design objectives and their necessary maximum control forces are computed fur the production of actuator. Probabilities of maximum responses match statistical data from simulation results well.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.06a
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• pp.138-143
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• 2000

This paper addresses experimental results carried out to investigate the transmission of seat vibration to the head for Korean. Vertical seat vibration in the frequency range of 0.5-30 Hz was applied to a seated Korean male subject. To examine the intra-variable effects on transmissibility, five different postures and three different vibration excitation levels were considered. The applied acceleration and head accelerations of the seated subject were measured simultaneously by using a 6-axes bite-bar. Detailed experimental results of measured transmissibilities are illustrated for each posture and/or vibration excitation level. They are found to allow the identification of dynamic characteristics of Korean seated body for various real vibration environments. Furthermore, they are expected to be very useful in designing new seats for automotive and railway vehicles and in improving their vibration ride quality.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2013.04a
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• pp.321-326
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• 2013

This paper investigates the magnetic excitation force of a surface-mounted permanent magnet (SPM) motor according to the change of pole/slot combination. The characteristics of magnetic flux and radial magnetic force (RMF) due to pole/slot combination were analyzed by using magnetic circuit analysis. Also, the RMF of motors with the variable pole/slot combination was numerically simulated by using the finite element analysis to verify the result of the magnetic circuit analysis. This research shows that RMF ripple is reduced when the number of pole is smaller than the number of slot.

• Journal of KSNVE
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• v.9 no.6
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• pp.1157-1165
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• 1999

Dynamic stability of a flying structure undertaking constnat and pulsating thrust force is investigated in this paper. The equations of motion of the structure, which is idealized as a free-free beam, are derived by using the hybrid variable method and the assumed mode method. The structural system includes a directional control unit to obtain the directional stability. Unstable regions due to periodically pulsating thrust forces are obtained by using the Floquet's theory. Stability diagrams are presented to illustrate the influence of the constant force, the location of gimbal, and the frequency of pulsating force. The validity of the diagrams are confirmed by direct numerical simulations of the dynamic system.

• Journal of KSNVE
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• v.10 no.6
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• pp.1017-1021
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• 2000

This paper addresses experimental results carried out to investigate the characteristics of dynamic mass for Korean. Vertical seat vibration in the frequency range of 0.5-30 Hz was applied to a seated Korean male subject. To examine the intra-variable effects on dynamic mass, five different postures and three different vibration excitation levels were considered. The applied acceleration and transmitted force to the hip of the seated subject were measured simultaneously. Detailed experimental results of measured dynamic mass are illustrated for each posture and/or vibration excitation level. Maximum peaks of around 5 Hz were observed for most experimental cases. They are found to allow the identification of dynamic characteristics of Korean seated body for various real vibration environments. Furthermore, they are expected to be very useful in designing new seats for automotive and railway vehicles and in improving their vibration ride duality.

• Earthquakes and Structures
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• v.9 no.5
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• pp.1115-1132
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• 2015

The study considers earthquake shake table testing of bending-torsion coupled structures under multi-component stationary random earthquake excitations. An experimental procedure to arrive at the optimal excitation cross-power spectral density (psd) functions which maximize/minimize the steady state variance of a chosen response variable is proposed. These optimal functions are shown to be derivable in terms of a set of system frequency response functions which could be measured experimentally without necessitating an idealized mathematical model to be postulated for the structure under study. The relationship between these optimized cross-psd functions to the most favourable/least favourable angle of incidence of seismic waves on the structure is noted. The optimal functions are also shown to be system dependent, mathematically the sharpest, and correspond to neither fully correlated motions nor independent motions. The proposed experimental procedure is demonstrated through shake table studies on two laboratory scale building frame models.

• Journal of the Korean Graphic Arts Communication Society
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• v.1 no.1
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• pp.7-41
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• 1983

Reproduced colors which are half-tone printed at the rate of 10,20,30, ...100% half-tone dot area by each process ink- cyan, magenta, yellow and at the rates of 0,30,60, 100% half-tone dot areas by the mean color mixing of black, cyan, magenta and yellow, are colorimetric analyzed by make use of the 1931 CIE XYZ system of color specification and matching the Munsell color system. Espacially, magenta and secondary colors which are contained magenta, do not have good uniformity and proportionalization in the dominant wavelength and the excitation purity. Half-tone colors without reflection of blue light, are reproduced ideal color with the excitation purity 100% in wavelengths from 555nm to 600nm.